Thermactivation of catalysts comprising catalytic metals-free crystalline zeolitic molecular sieve particles dispersed in a gel matrix

ABSTRACT

Method of activating a catalyst composite comprising particles of a catalytic metals-free crystalline zeolitic molecular sieve dispersed in a gel matrix comprising silica-alumina, a Group VI hydrogenating component and a Group VIII hydrogenating component, which method comprises heating said catalyst composite in an oxygen-containing gas stream at 1200° to 1600°F. for 0.25 to 48 hours, and the catalyst composite so activated.

RELATED APPLICATION

This application is a continuation of patent application Ser. No.757,503 filed Sept. 4, 1968, now abandoned.

INTRODUCTION

In Joseph Jaffe copending application Ser. No. 749,836, filed Aug. 2,1968, for "Hydrotreating Catalyst and Process," there is described anovel and unusually effective hydrofining-hydrocracking catalyst. Saidcatalyst comprises a crystalline zeolitic molecular sieve componentsubstantially free of any catalytic metal or metals, a silica-containinggel component, a Group VI hydrogenating component, and a componentselected from titanium, zirconium, thorium, hafnium, and compoundsthereof. It has now been found that catalysts of this general type,either with or without a Group IV component, can be even furtherimproved in various respects by a novel heat treatment procedure, whichserves both to activate and stabilize the catalyst. Said heat treatmentprocedure, hereinafter for convenience called an activation orthermactivation treatment or procedure, is applied to the total catalystcomposite, following dispersion of the crystalline zeolitic molecularsieve component in the gel matrix.

STATEMENT OF INVENTION

In accordance with the present invention catalysts of the aforesaid typeare thermactivated in an oxygen-containing gas stream at temperatures inthe range 1,200° to 1,600°F., preferably 1,250° to 1,400°F., for 0.25 to48 hours. The oxygen-containing gas stream, which may be air, preferablyis as dry as practicable. The improved results obtainable with theprocess of the present invention are optimized as the gas stream becomesextremely dry; although for most practical purposes the gas stream needbe only as dry as ambient air, greater dryness is preferred. Thoseskilled in the art will be aware of various methods for drying the gasstream to any desired extent.

Although the process of the present invention is applicable toactivation of catalysts of the aforesaid type with a wide range ofsilica content, it is especially useful with such catalysts that containless than 40 weight percent silica in the total catalyst, and less than35 weight percent silica in the catalyst matrix.

Further in accordance with the present invention there is provided themethod of activating a catalyst composite comprising:

A. A gel matrix comprising:

A. at least 15 weight percent silica,

B. alumina, in an amount providing an aluminum-to-silica weight ratio of15/85 to 80/20,

C. nickel or cobalt, or the combination thereof, in the form of metal,oxide, sulfide or any combination thereof, in an amount of 1 to 10weight percent of said matrix, calculated as metal,

D. molybdenum or tungsten, or the combination thereof, in the form ofmetal, oxide, sulfide or any combination thereof, in an amount of 5 to25 weight percent of said matrix, calculated as metal;

B. A crystalline zeolitic molecular sieve substantially in the ammoniaor hydrogen form, substantially free of any catalytic loading metal ormetals, said sieve further being in particulate form and being dispersedthrough said matrix;

said catalyst composite being further characterized by an average porediameter below 100 Angstroms and a surface area above 200 square metersper gram;

which method comprises heating said catalyst composite in anoxygen-containing gas stream at temperatures in the range 1200° to1600°F. for 0.25 to 48 hours.

Further in accordance with the present invention there is provided acatalyst composite comprising:

A. A gel matrix comprising:

a. at least 15 weight percent silica,

b. alumina, in an amount providing an alumina-to-silica weight ratio of15/85 to 80/20,

c. nickel or cobalt, or the combination thereof, in the form of metal,oxide, sulfide or any combination thereof, in an amount of 1 to 10weight percent of said matrix, calculated as metal,

d. molybdenum or tungsten, or the combination thereof, in the form ofmetal, oxide, sulfide or any combination thereof, in an amount of 5 to25 weight percent of said matrix, calculated as metal;

B. A crystalline zeolitic molecular sieve substantially in the ammoniaor hydrogen form, substantially free of any catalytic loading metal ormetals, said sieve further being in particulate form and being dispersedthrough said matrix;

said catalyst composite being further characterized by an average porediameter below 100 Angstroms and a surface area above 200 square metersper gram; said catalyst composite being further characterized byhydrocracking activities and stabilities developed therein by heatingsaid catalyst composite in an oxygen-containing gas stream attemperatures in the range 1200°to 1600°F. for 0.25 to 48 hours.

The gel matrix of the aforesaid catalyst composite additionally maycomprise titanium, zirconium, thorium, hafnium, or any combinationthereof, in the form of the metal, oxide, sulfide or any combinationthereof, in an amount of 1 to 10 weight percent of said matrix,calculated as metal.

The reference to a crystalline zeolitic molecular sieve "substantiallyfree of any catalytic loading metal or metals" means that the molecularsieve contains no more than 0.5 weight percent of catalytic metal ormetals, based on the sieve. The catalytic metal or metals include theGroup VI and VIII metals, excluding sodium.

EXAMPLES

The following examples are given for the purpose of further illustratingthe process and catalyst of the present invention, without limiting thescope thereof.

Example 1

A cogelled catalyst (Catalyst A) of the following composition wasprepared:

                         Wt. % of Total                                           Component            Catalyst                                                 ______________________________________                                        NiO                  8.2                                                      WO.sub.3             18.2                                                     TiO.sub.2            5.6                                                      Al.sub.2 O.sub.3     24.0                                                     SiO.sub.2            24.0                                                     Crystalline zeolitic                                                           molecular sieve,                                                              "Y" form            20.0                                                     Total                100.0                                                    ______________________________________                                    

The catalyst was prepared by the following steps, using sufficientquantities of the various starting materials to produce theabove-indicated weight percentages of the components of the finalcatalyst:

1. An aqueous acidic solution was prepared, containing AlCl₃, TiCl₄NiCl₂ and acetic acid.

2. Three alkaline solutions were prepared: (1) a sodium silicatesolution; (2) a sodium tungstate solution; and (3) an ammonia solutioncontaining sufficient excess ammonia so that upon combining the alkalinesolutions with the acidic solution coprecipitation of all of themetal-containing components would occur at a neutral pH of about 7.

3. The acidic and alkaline solutions were combined, and coprecipitationof all of the metal-containing components of those solutions occurred ata pH of about 7, resulting in a slurry.

4. Linde "Y" crystalline zeolite molecular sieve in finely divided formwas added to the slurry.

5. The molecular sieve-containing slurry was filtered to produce amolecular sieve-containing hydrogel filter cake, which was washedrepeatedly with dilute ammonium acetate solution to remove sodium andchloride ionic impurities from both the hydrogel and the molecular sievecontained therein.

6. The molecular sieve-containing hydrogel was dried in anair-circulating oven and then was activated in flowing air at 950°F. for5 hours.

The finished catalyst was characterized by a surface area of about 400M² /g., a pore volume of about 0.4 cc./g., an average pore diameter ofabout 40 Angstroms, and a molecular sieve component substantially freeof catalytic metals; that is, substantially all of the nickel, tungstenand titanium in the catalyst was located in the gel portion of thecatalyst rather than in the molecular sieve component thereof.

Example 2

A cogelled catalyst (Catalyst B), of exactly the same composition asCatalyst A of Example 1, was prepared. The catalyst was prepared inexactly the same manner as Catalyst A of Example 1 except that uponcompletion of the activation at 950°F. for 5 hours the catalyst wasfurther activated at 1,275°F. for 2 hours.

The finished catalyst was characterized by a surface area of about 350M² /g., a pore volume of about 0.4 cc./g., an average pore diameter ofabout 40 Angstroms. The molecular sieve component remained substantiallyfree of catalytic metals.

Example 3

A cogelled catalyst (Catalyst C, a comparison catalyst) was prepared.The composition was similar to that of Catalyst A of Example 1 exceptthat it contained only 10 weight percent of crystalline zeoliticmolecular sieve and the weight percentages of the other components wereproportionally adjusted. Catalyst C was prepared in exactly the samemanner as Catalyst A of Example 1, including a final activationtreatment in flowing air at 950°F. for 5 hours.

Example 4

A cogelled catalyst (Catalyst D) of the following composition wasprepared:

                         Wt. % of Total                                           Component            Catalyst                                                 ______________________________________                                        NiO                  11.4                                                     WO.sub.3             11.3                                                     ZrO.sub.2            9.0                                                      Al.sub.2 O.sub.3     27.0                                                     SiO.sub.2            31.3                                                     Crystalline zeolitic                                                           molecular sieve,                                                              sodium "Y" form     10.0                                                     Total                100.0                                                    ______________________________________                                    

The catalyst was prepared in exactly the same manner as Catalyst A ofExample 1, except that ZrOCl₂ was used instead of TiCl₄. The finalactivation treatment, as in the case of Catalyst A of Example 1, was inflowing air at 950°F. for 5 hours.

The finished catalyst was characterized by a surface area of 420 M² /g.,a pore volume of 0.347, an average pore diameter of 33 Angstroms, and amolecular sieve component substantially free of catalytic metals; thatis, substantially all of the nickel, tungsten and zirconium in thecatalyst was located in the gel portion of the catalyst rather than inthe molecular sieve component thereof.

Example 5

A cogelled catalyst (Catalyst E), of exactly the same composition asCatalyst D of Example 4, was prepared. The catalyst was prepared inexactky the same manner as Catalyst D of Example 4, except that uponcompletion of the activation at 950°F. for 5 hours the catalyst wasfurther activated at 1350°F. for 2 hours.

The finished catalyst was characterized by a surface area of 374 M² /g.,a pore volume of 0.353, and an average pore diameter of 38 Angstroms.The molecular sieve component remained substantially free of catalyticmetals.

Example 6

Catalysts A and C of Examples 1 and 3, respectively, were separatelyused to hydrocrack separate portions of a light cycle oil of thefollowing description:

    Gravity, °API 19.5                                                     Aniline point, °F.                                                                          62                                                       Sulfur content, wt.% 0.43                                                     Nitrogen content, ppm                                                                              330                                                      ASTM D-1160 Distillation                                                             ST/5    381/471                                                               10/30   492/532                                                               50      568                                                                   70/90   598/635                                                               95/EP   648/681                                                    

The hydrocracking was accomplished at the following conditions:

    Hydrogen pressure, psig                                                                             1100                                                    Per-pass conversion to products                                                boiling below 400°F., vol.%                                                                 80                                                      Liquid Hourly Space Velocity                                                                        0.9                                                     Starting temperature  As indicated                                                                  below                                               

The hydrocracking was accomplished on a recycle basis, that is, withrecycle to the hydrocracking zone from the effluent thereof materialsboiling above 400°F.

The hydrocracking activities of the two catalysts, as measured by theoperating temperatures necessary to achieve the indicated per-passconversion, and the fouling rates of the two catalysts, as indicated bythe hourly rise in temperature necessary to maintain the indicatedper-pass conversion, were:

                   Catalyst A                                                                              Catalyst C                                           ______________________________________                                        Operating temperature,                                                        °F.       725         725                                              Fouling rate, °F./hr.                                                                   0.07        0.03                                             ______________________________________                                    

From the foregoing, it may be seen that Catalyst A is as active ascomparison Catalyst C, but that it has poor stability compared withCatalyst C.

Example 7

Catalysts B and C of Examples 2 and 3, respectively, were separatelyused to hydrocrack separate portions of a gas oil of the followingdescription:

    Gravity, °API 29.0                                                     Aniline point, °F.                                                                          165                                                      Sulfur content, wt.% 1.9                                                      Nitrogen content, ppm                                                                              390                                                      ASTM D-1160 Distillation                                                             ST/5    486/551                                                               10/30   577/629                                                               50      674                                                                   70/90   716/791                                                               95/EP   825/948                                                    

The hydrocracking was accomplished at the following conditions:

    Hydrogen pressure, psig                                                                              1300                                                   Per-pass conversion to products                                                boiling below 550°F., vol.%                                                                  70                                                     Liquid hourly space velocity v/v/hr.                                                                 1.5                                                    Starting temperature   As indicated                                                                  below                                              

The hydrocracking was accomplished on a recycle basis, that is, withrecycle to the hydrocracking zone from the effluent thereof materialsboiling above 550°F.

The hydrocracking activities of the two catalysts, as measured by theoperating temperatures necessary to achieve the indicated per-passconversion, and the fouling rates of the two catalysts, as indicated bythe hourly rise in temperature necessary to maintain the indicatedper-pass conversion, were:

                   Catalyst B                                                                              Catalyst C                                           ______________________________________                                        Operating Temperature, °F.                                                              705         706                                              Fouling rate, °F./Hr.                                                                   0.02        0.02                                             ______________________________________                                    

From the foregoing, it may be seen that Catalyst B has essentially thesame activity and the same stability as comparison Catalyst C.Accordingly, the heat treatment activation of Catalyst A at 1275°F. for2 hours resulted in a catalyst, Catalyst B, having a stability markedlybetter than that of Catalyst A, and this was achieved without harm tothe activity of the catalyst.

Example 8

Catalysts D and E of Examples 4 and 5, respectively, were separatelyused to hydrocrack separate portions of a hydrofined Mid-Continentstraight-run gas oil of the following description:

    Gravity, °API                                                                              31.5                                                      Aniline point, °F.                                                                         172                                                       Nitrogen content, ppm                                                                             0.44                                                      Boiling range, °F.                                                                         400-800                                               

The hydrocracking was accomplished at the following conditions:

    Temperature, °F.                                                                             570                                                     Liquid hourly space velocity                                                                        2                                                       Total pressure, psig  1,200                                                   Total gas rate, SCF/bbl.                                                                            12,000                                              

After 98 hours on stream, the activity indices of the two catalysts weredetermined. In each case, the activity index was defined as thedifference between the API gravity of the liquid product and the APIgravity of the liquid feed. The results were:

                   Catalyst D                                                                              Catalyst E                                           ______________________________________                                        Activity Index   14.9        20.2                                             ______________________________________                                    

From the foregoing, it may be seen that Catalyst E had a greaterhydrocracking activity than Catalyst D. Accordingly, the heat treatmentactivation of Catalyst D at 1350°F. for 2 hours resulted in a catalyst,Catalyst E, having an activity index markedly better than that ofCatalyst D.

CONCLUSIONS

Applicants do not intend to be bound by any theory for the unexpectedlysuperior activities and stabilities of the catalysts treated accordingto the process of the present invention. They assume that the favorableresults are largely attributable to, and unique to, the particularcombination of catalytic components used, in further combination withthe particular method by which the thermactivation treatment isconducted.

Although only specific embodiments of the present invention have beendescribed, numerous variations can be made in these embodiments withoutdeparting from the spirit of the invention, and all such variations thatfall within the scope of the appended claims are intended to be embracedthereby.

What is claimed is:
 1. A catalyst composite comprising:A. a gel matrixcomprising:a. at least 15 weight percent silica, b. alumina, in anamount providing an alumina-to-silica weight ratio of 15/85 to 80/20, c.nickel or cobalt, or the combination thereof, in the form of metal,oxide, sulfide, or any combination thereof, in an amount of 1 to 10weight percent of said matrix, calculated as metal, d. molybdenum ortungsten, or the combination thereof, in the form of metal, oxide,sulfide, or any combination thereof, in an amount of 5 to 25 weightpercent of said matrix, calculated as metal; B. a crystalline zeoliticmolecular sieve substantially in the ammonia or hydrogen form,substantially free of any catalytic loading metal or metals, said sievefurther being in particulate form and being dispersed through saidmatrix;said catalyst composite being further characterized by an averagepore diameter below 100 Angstroms and a surface area above 200 squaremeters per gram; said catalyst composite being further characterized byhydrocracking activities and stabilities developed therein by heatingsaid catalyst composite in an oxygen-containing gas stream attemperatures in the range 1200°F. to 1600°F. for 0.25 to 48 hours.
 2. Acatalyst composite as in claim 1 wherein said gel matrix furthercomprises titania.
 3. A catalyst comprising a silica-alumina matrixhaving dispersed in it particles of a low-sodium molecular sievezeolite, the silica-alumina matrix having dispersed in it a Group VImetal or metal compound and a Group VIII metal or metal compound and thezeolite being substantially free of chemically or physically bondedmetals or metal compounds having appreciable catalytic activity forhydrogenation; said catalyst being further characterized byhydrocracking activities and stabilities developed therein by heatingsaid catalyst in an oxygen-containing gas stream at temperatures in therange 1200° to 1600°F. for 0.25 to 48 hours.
 4. A catalyst comprising acrystalline zeolitic molecular sieve of the ammonia or hydrogen form andsubstantially free of metals or metal compounds having catalyticactivity for hydrogenation dispersed in a hydrocracking catalyst matrixcomprised of silica-alumina having dispersed in it 1 to 10% by weight ofnickel in the formm of metal, metal oxide or metal sulfide and 5 to 25%by weight of molybdenum or tungsten in the form of metal, metal oxide ormetal sulfide, said catalyst being further characterized byhydrocracking activities and stabilities developed therein by heatingsaid catalyst in an oxygen-containing gas stream at temperatures in therange 1200° to 1600°F. for 0.25 to 48 hours.